One of the most challenging problems in total synthesis of natural products and modern antibiotics is controlling the stereochemistry in the formation of new bonds. There have been great strides in recent years in the application of organometallics and transition metal catalysts to drug synthesis. Research will be undertaken to develop new transitional metal reagents and catalysts for controlling stereochemistry in synthetically useful reactions. A new approach using transitional metal reagents and catalysts containing unsymmetrical tridentate ligands will be developed for stereocontrolled reactions appropriate for antibiotic synthesis. We anticipate, for example, the generation of new reagents applicable to key steps in asymmetric syntheses of beta-lactams, which are important to the development of modern antibiotics based on analogues of penicillin.